What is a patch?

Things to know about patches

• Patches are cumulative. You don't need to apply multiple patches sequentially to get to the desired patch level. You can move up (or down) one or more patch levels with a single operation.
• The Level option ( -l) allows you to downgrade or upgrade to any patch level (within the maximum available in the cumulative patch).
• The Rollback option (-r) allows you to revert the site to the previous patch level it was at, before the current patch was applied.
• The Uninstall option (-u) allows you to downgrade the patch level on the site by one.
• When a patch installation fails you can use the Force option (-F) to proceed, without manually uninstalling previous patches.
• The system displays a summary of what happens during the patch installation.
• Before proceeding with the patch installation, you can use the "dry run" mode (-t option) to see the summary of actions that will be performed during the installation.

Best practices

Before applying a patch, note the following principles.

• The upgrade scripts are usable only with an existing installation.
• No data migration will occur if any changes have been made to the database schema.
• You must use the sudo command or have an account that is equivalent to root in order to complete a patch installation successfully.